This invention relates to anti-theft devices for vehicles such as automobiles, motorcycles or the like. More particularly, the present invention relates to the incorporation of a series of operator-controlled switches into the electrical system associated with the engine in which the switches must be set to a predetermined, code-like configuration before the engine can be started.
In each embodiment of the invention, the line from the battery to the starter motor has a relay-operated switch which is normally open to prevent operation of the starter motor. The relay is connected to the battery through a self-locking gating device, such as an SCR, the operation of which is controlled by setting one of the code input switches to a predetermined preliminary position. That code input switch then must be switched to a second predetermined position to connect the battery with the ignition coil. Preferably, a second multi-position code input switch is connected between the other side of the ignition coil and the points in a manner which also requires setting of that second input switch to a predetermined position.
In a modified form of the invention, the second code input switch usually must be set to an inoperative position while the first code input switch is being sequenced as described above.
In a further embodiment of the invention, a third code input switch is added and is connected with respect to the points to short the points in all but one of the switch positions. In another embodiment of the invention, a fourth code input switch may be provided between the gating device and the relay. This adds a fourth required code input and also requires a specific sequence of operation of the first and fourth code input switches in that the fourth code input switch must be set to a predetermined position before the first code input switch is operated.
In each embodiment of the invention, the relay deactuates automatically when the main ignition switch is shut off and the switching system becomes automatically disabled, thus requiring that the code input switches be reset in order to restart the engine. This insures that the engine cannot be restarted in the event that the operator forgets to scramble the code input switches when leaving the automobile.
It is among the general objects of the invention to provide an improved vehicle anti-theft device.
A further object of the invention is to provide a vehicle anti-theft system which precludes operation of the electrical system of the vehicle engine until a number of code input switches are set to predetermined positions and in a predetermined sequence.
Another object of the invention is to provide a system of the type described which is self-disabling when the engine ignition system is shut off.